1. Field
This disclosure relates to antennas for portable microwave and millimeter wave systems.
2. Description of the Related Art
Microwave and millimeter wave communications, sensor, and directed energy systems commonly use reflective beam forming elements to shape and direct an output beam. The angular size, or divergence, of the output beam may be determined, at least in part, by diffraction from the aperture defined by the final beam forming element, commonly called the “main reflector” or the “primary reflector”. The primary reflector is typically a geometrically curved reflector, such as a parabolic reflector, to convert a diverging wavefront from a source of microwave radiation into a collimated or nearly collimated output wavefront.
To form a narrow output beam, the primary reflector typically has a large surface area. However, a large-area primary reflector may be inconvenient or impractical in a portable system. The primary reflectors used in current portable microwave and millimeter wave system generally represent a compromise between the output beam size and portability.
Portable communications, sensor, and directed energy systems could benefit from having a foldable primary reflector able to provide both a large aperture when the system is in use and a compact form factor when the system is transported.
Throughout this description, elements appearing in figures are assigned three-digit reference designators, where the most significant digit is the figure number and the two least significant digits are specific to the element. An element that is not described in conjunction with a figure may be presumed to have the same characteristics and function as a previously-described element having a reference designator with the same least significant digits.